1. Field of the Invention
The present invention relates generally to a relatively simple photopolarimeter and method for measuring the state of polarization of a light beam, and more particularly pertains to a unique and simple photopolarimeter and method for measuring at least one parameter defining the state of polarization of a light beam which does not require any of the usual prior art polarizing elements such as wave retarders and polarizers.
2. Discussion of the Prior Art
Many photopolarimeters have been proposed and built to measure the state of polarization of light. See, for example, R. M. A. Azzam and D. L. Coffeen, Optical Polarimetry Vol. 112 of Proc. Soc. Photo-Opt. Intrum. Eng. (SPIE, Bellingham Wash., 1977). Generally, the polarimeters employ a sequence of polarizing optical elements such as wave retarders and linear polarizers followed by a photodetector. Polarization sensitivity of photodetectors is considered an annoyance and a possible source of error to be eliminated.
Prior art ellipsometers also employ a sequence of polarizing optical elements followed by a photodetector to measure the polarization state of incident light. U.S. Pat. No. 4,053,232 discloses a rotating ellipsometer wherein the light beam is passed through a polarizer before being reflected from a sample surface. The reflected beam is passed through an encoder, a compensator, and an analyzer before being incident on a photodetector.